The invention relates to a pyrotechnic pretensioner for a safety system in a vehicle comprising an inflator having a propelling charge as well as an igniter and comprising a housing including a pressure chamber provided therein into which gas can flow and in which a piston can be displaced by the gas.
A pyrotechnic pretensioner, for example an end fitting pretensioner for a seat belt in a vehicle includes an elongate cylindrical housing in which a piston is supported to be movable in the longitudinal direction. On said piston a tension transmission means is fastened which is connected to a component of a vehicle safety system such as an end fitting of a seat belt. In order to displace the piston in the longitudinal direction and thus to achieve, for example, tensioning of the seat belt, a pyrotechnic inflator adapted to generate excess pressure in the chamber for displacing the piston is provided. Usually the housings and the inflators are separately manufactured and are assembled immediately prior to being mounted in a vehicle. For this purpose, a coupling member to which the inflator is connected is provided on the housing. However, this requires increased manufacturing efforts. Moreover, the assembly of these pretensioners is very complicated.
From the state of the art also inflators are known in which at an end piece closing the pressure chamber a seat for the inflator is formed into which the inflator can be simply inserted. However, also in these pretensioners additional components are required to fix the inflator in the end piece and thus on the housing.
Alternatively, there are also known pretensioners in which the propelling charge of the inflator is arranged already in the pressure chamber. However, the assembly of such pretensioners is equally very complicated, as the propelling charge has to be positioned within the pressure chamber and has to be safely protected against external influences.